Title Page
Contents
ABSTRACT 13
1. Introduction 15
1.1. Definition of amorphous and crystalline materials 15
1.2. Properties of amorphous and crystalline materials 17
1.2.1. Structural properties 17
1.2.2. Thermal properties 17
1.2.3. Soft magnetic properties 20
1.3. Characteristics of Fe-Co-based alloys 25
2. Experimental Methods 26
2.1. Synthesis of amorphous and crystalline alloys 26
2.2. Structural analysis 31
2.2.1. X-ray diffraction 31
2.3. Thermal analysis 37
2.3.1. Differential scanning calorimetry 37
2.4. Magnetic analysis 38
2.4.1. Vibrating sample magnetometer 38
2.4.2. DC B-H loop tracer 40
3. Result and Discussion 41
3.1. Fe-Co-B-Si-Nb alloy system with varying Fe/Co ratio 41
3.1.1. Design of alloys 41
3.1.2. Analysis of the characteristics of alloys 42
3.2. Fe-Co-V alloy system with varying Fe/Co ratio 54
3.2.1. Design of alloys 54
3.2.2. Analysis of the characteristics of alloys 54
3.3. Fe-Co-V-M(M=Nb or Ni) alloy system 64
3.3.1. Design of alloys 64
3.3.2. Analysis of the characteristics of alloys 64
4. Summary and Conclusion 71
5. Reference 72
ABSTRACT IN KOREAN 76
Table 1. Tx, Tg, △Tx of the (FexCo1-x)72B19.2Si4.8Nb4 (0 ≤ x ≤ 1) as-...[이미지참조] 47
Table 2. Ms of the (FexCo1-x)72B19.2Si4.8Nb4 (0 ≤ x ≤ 1) as-spun ribbons.[이미지참조] 51
Table 3. Bs and Wh of the FexCo98-xV2 (49 ≤ x ≤ 93) as-spun ribbons.[이미지참조] 60
Figure 1. Schematic image of crystal and amorphous structure. 16
Figure 2. DSC curve with Tg, Tx, and Tm.[이미지참조] 19
Figure 3. Hysteresis loop with Ms, Hc, μ, and Wh.[이미지참조] 21
Figure 4. Schematic image comparing the hysteresis loop between... 23
Figure 5. Schematic diagram of melt-spinning technique. 28
Figure 6. Schematic representation of injection casting technique. 30
Figure 7. Schematic image of the XRD. 32
Figure 8. Illustration of explaining Bragg's law in XRD. 33
Figure 9. XRD spectrum in crystalline and amorphous solids. 35
Figure 10. Schematic diagram of VSM. 39
Figure 11. XRD patterns of the (FexCo1-x)72B19.2Si4.8Nb4 (0 ≤ x ≤ 1)...[이미지참조] 44
Figure 12. DSC graphs of the (FexCo1-x)72B19.2Si4.8Nb4 (0 ≤ x ≤ 1) as-...[이미지참조] 46
Figure 13. Trend of Tx, Tg, △Tx of the (FexCo1-x)72B19.2Si4.8Nb4 (0 ≤ x...[이미지참조] 48
Figure 14. Hysteresis loops of the (FexCo1-x)72B19.2Si4.8Nb4 (0 ≤ x ≤...[이미지참조] 50
Figure 15. Ms tendency of the (FexCo1-x)72B19.2Si4.8Nb4 (0 ≤ x ≤ 1)...[이미지참조] 52
Figure 16. XRD spectrum of the Fe49Co49V2 as-spun ribbons varying...[이미지참조] 56
Figure 17. XRD graph of the as-spun FexCo98-xV2 (49 ≤ x ≤ 93) ribbon.[이미지참조] 57
Figure 18. Hysteresis loops of the FexCo98-xV2 (49 ≤ x ≤ 93) as-...[이미지참조] 59
Figure 19. Bs tendency of the FexCo98-xV2 (49 ≤ x ≤ 93) as-spun ribbons.[이미지참조] 61
Figure 20. Wh tendency of the FexCo98-xV2 (49 ≤ x ≤ 93) as-spun ribbons.[이미지참조] 62
Figure 21. XRD patterns of the (FexCo0.98-xV0.02)100-yAy (x=0.49, 0.50,...[이미지참조] 65
Figure 22. Bs tendency of the (FexCo0.98-xV0.02)100-yAy (x=0.49, 0.50,...[이미지참조] 67
Figure 23. Hc tendency of the (FexCo0.98-xV0.02)100-yAy (x=0.49, 0.50,...[이미지참조] 68
Figure 24. Wh tendency of the (FexCo0.98-xV0.02)100-yAy (x=0.49, 0.50,...[이미지참조] 69